Table 1 Model parameters: baseline values, ranges, and distributions for sensitivity analysis

Weibull survival model of OS of PEP

Weibull survival model of OS of EP

Scale = 0.035532,

Shape = 1.209467

Scale = 0.021012,

Shape = 1.497332

–

–

–

–

[10]

–

–

Weibull survival model of PFS of PEP

Weibull survival model of PFS of EP

Scale = 0.06893,

Shape = 1.40287

Scale = 0.02532,

Shape = 2.21179

-

–

–

–

[10]

–

–

Risk for main adverse events in PEP group

 Risk of neutropenia

0.435

0.348

0.522

[10]

Beta

 Risk of anemia

0.157

0.126

0.189

[10]

Beta

 Risk of thrombocytopenia

0.139

0.111

0.167

[10]

Beta

 Risk of leucopenia

0.117

0.094

0.140

[10]

Beta

 Risk of pneumonia

0.067

0.054

0.080

[10]

Beta

Risk for main adverse events in EP group

 Risk of neutropenia

0.408

0.326

0.490

[10]

Beta

 Risk of anemia

0.152

0.121

0.182

[10]

Beta

 Risk of thrombocytopenia

0.112

0.090

0.134

[10]

Beta

 Risk of leucopenia

0.094

0.075

0.113

[10]

Beta

Utility

 Utility PFS in first-line treatment

0.840

0.672

1.008

[12]

Beta

 Utility PD

0.473

0.378

0.568

[13]

Beta

Disutility due to AEs

 Neutropenia

0.09

0.072

0.108

[13]

Beta

 Anemia

0.073

0.058

0.088

[13]

Beta

 Leucopenia

0.09

0.072

0.108

[13]

Beta

 Pneumonia

0.09

0.072

0.108

[14]

Beta

Thrombocytopenia

0.02

0.016

0.024

[15]

Beta

Drug cost, $/per mg

 Pembrolizumab

20,370.80

16,296.64

24,444.96‬

[20]

Gamma

 Etoposide

1,663.73

1,330.98

1996.47

[20]

Gamma

 Carboplatin

85.83

68.66

103.00

[20]

Gamma

 Cisplatin

51.78

41.42

62.13

[20]

Gamma

 Topotecan

199.87

159.90

239.84

[20]

Gamma

Expenditures on main adverse events, $

 Leucopenia

6,831.97

5,465.58

8,198.37

[21]

Gamma

 Neutropenia

733.36

586.69

880.03

[22]

Gamma

 Anemia

1,199.86

959.89

1,439.83

[22]

Gamma

 Thrombocytopenia

851.51

681.21

1,021.82

[22]

Gamma

 Pneumonia

5,646.88

4,517.51

6,776.26

[22]

Gamma

Laboratory per cycle

315.14

252.11

378.17

[23]

Gamma

Tumor imaging per cycle

231.10

184.88

167.60

[24]

Gamma

Administration per cycle

139.67

111.74

167.60

[25]

Gamma

Discount rate

0.03

–

–

[11]

–